What is "Blur 3.4.2"?

Quick note, I was rooted but just unrooted and started clean last night. I'm currently on .340, I flashed the FULL SBF last night.

Anyways. I keep seeing all these Blur 3.4.2 threads out there and it's sad to say, but I'm still not sure what it is? Can someone please elaborate to me in detail what Blur 3.4.2 is. Is Blur 3.4.2 a ROM, just a new build, an update to .340, etc.? I'm confused on what it is. I do have the TBH app that has this so I can download it if needed. I'm just curious to know what the whole deal about this is and if its worth updating to this?

It's a leaked blur version from p3droid. It will probably be an ota eventually unless moto decides to skip it and go straight to gingerbread. It's probably not worth updating to, especially if you're running a custom ROM.